Pelvic floor disorders afflict many women. According to some studies, about 1 out of 11 women needs surgery for a pelvic floor disorder during her lifetime. The pelvic floor generally includes muscles, ligaments, and tissues that collectively act to support anatomical structures of the pelvic region, including the uterus, the rectum, the bladder, and the vagina. Pelvic floor disorders include vaginal prolapse, vaginal hernia, cystocele, rectocele, and enterocele. Such disorders are characterized in that the muscles, ligaments and/or tissues are damaged, stretched, or otherwise weakened, which causes the pelvic anatomical structures to fall or shift and protrude into each other or other anatomical structures.
Moreover, pelvic floor disorders often cause or exacerbate female urinary incontinence (UI). Urinary incontinence affects over 13 million men and women of all ages in the United States. Stress urinary incontinence (SUI) affects primarily women and is generally caused by two conditions, intrinsic sphincter deficiency (ISD) and hypermobility. These conditions may occur independently or in combination. In ISD, the urinary sphincter valve, located within the urethra, fails to close properly (coapt), causing urine to leak out of the urethra during stressful activity. Hypermobility is a condition in which the pelvic floor is distended, weakened, or damaged, causing the bladder neck and proximal urethra to rotate and descend in response to increases in intra-abdominal pressure (e.g., due to sneezing, coughing, straining, etc.). As a result, the patient's response time becomes insufficient to promote urethral closure and, consequently, the patient suffers from urine leakage and/or flow.
UI and pelvic floor disorders, which are usually accompanied by significant pain and discomfort, are typically treated by implanting a supportive sling in or near the pelvic floor region to support the fallen or shifted anatomical structures or to, more generally, strengthen the pelvic region by, for example, promoting tissue ingrowth. A popular treatment of SUI and uses a sling placed under the bladder neck or mid-urethra to provide a urethral platform. Placement of the sling limits the endopelvic fascia drop, while providing compression to the urethral sphincter to improve coaptation. Generally, the sling is placed close to the high-pressure zone with no elevation of the urethra. When abdominal pressure increases, the sling stops the descent of the urethra and functions as a mechanism for closing the urethra to prevent urine leakage. However, if too much tension is applied, the patient may go into urine retention, unable to void the bladder. This results in a pressure build-up in the bladder, which can lead to reflux of urine up the ureters and into the kidneys, eventually resulting in kidney damage, and, potentially, kidney loss. Alternatively, if too little tension is applied, the implanted sling may not perform its function as intended.
Clinically, in vaginal incision techniques, it is challenging to both optimally position the slings and optimally adjust the tension of the sling during implantation while working through a relatively small single vaginal incision. It is sometimes necessary to modify the sling tension after the initial implantation, especially if the patient's anatomy has changed, for example due to weight gain. It would also be desirable to provide improved methods for adjusting sling tension to compensate for tension changes in the sling over time. Therefore, improved surgically implantable slings, and methods to allow for adjustment of the sling tension are needed.